SMA to MMCX Cable Assemblies Amphenol RF SMA to MMCX Cable Assemblies are available in a wide variety of lengths ranging from 3' to 2m. Cable types include RG-174, RG-178, and RG-316. The SMA to MMCX RF cable assemblies are designed with brass material with gold plating. Amphenol RF SMA to MMCX Cable Assemblies offer 50Ω impedance and a frequency range of 1GHz to 6GHz.